MBE-Grown beta-Ga2O3-Based Schottky UV-C Photodetectors With Rectification Ratio similar to 10(7)

In this letter, we demonstrate high-performance vertical solar-blind Schottky photodetectors on MBE-grown homoepitaxial (010)-oriented beta-Ga2O3 films. The structure, consisting of (100 nm) beta-Ga2O3/(60 nm) n(++) beta-Ga2O3, was grown on a Fe-doped insulating (010) beta-Ga2O3 substrate. Ni/Au and indium were used as the Schottky and Ohmic contacts, respectively. The devices exhibited a rectification ratio of similar to 10(7) with turn-on voltage similar to 1 V and an ideality factor of 1.31. The extracted Schottky barrier height was 1.4 eV. The photodetectors showed low dark current of 0.3 nA at 5 V with a photo-todark current ratio of similar to 10(2) at 0 V. The devices exhibited a zero-bias responsivity of 4 mA/W at 254 nm corresponding to an external quantum efficiency similar to 3 %, with a UV-to-visible rejection ratio >10(3), showing true solar-blind operation. The transient response of the devices indicated rise/fall times of similar to 100 ms. Temperature-dependent current-voltage characteristics agree with the thermionic emission model.